Power Transformer Solution: Dual Enhancement Strategy Based on Insulation Material Optimization and Oil Quality Management

Rockwill

17yrs 700++ staff 108000m²+m² US$150,000,000+ China

Ⅰ. Core Challenges and Objectives

Challenges: During long-term operation, transmission transformers face two core issues: insulation material aging (leading to reduced insulation strength and diminished heat resistance) and transformer oil degradation (increased moisture content, impurity accumulation, rising acid number, etc.), which threaten equipment safety and service life.
Objectives: Through material upgrades and management reinforcement, significantly enhance the stability of insulation performance, inhibit the oil degradation process, and ultimately achieve improved transformer operational reliability, reduced maintenance costs, and extended service life.

II. Detailed Solution Description

Pressboard: Select new cellulose-based insulation paper (such as optimized T-UPS) or synthetic fiber insulation materials (e.g., polyaramid fibers like Nomex) with excellent thermal stability (e.g., H-class or higher thermal rating) and anti-aging capabilities. Compared to traditional materials, they better maintain mechanical strength and electrical performance under short-circuit current impacts and high-temperature operating conditions.
Insulating Oil: Utilize high-performance refined mineral oils or synthetic ester insulating oils. Refined oils feature lower sulfur content and higher oxidation resistance; synthetic esters offer significant advantages including excellent biodegradability, ultra-high flash point, and low hygroscopicity, making them particularly suitable for harsh environments or scenarios with high fire safety requirements.

Structural Optimization: Conduct refined design (e.g., simulation to optimize electric field distribution) for key components such as insulation barriers, angle rings, and spacers, ensuring uniform insulation layer thickness without weak points or structural stress concentrations.
Process Control: Strictly implement vacuum impregnation processes during manufacturing and assembly to ensure thorough saturation of insulation paper, eliminating internal defects like bubbles and voids, thereby improving overall insulation strength and dielectric performance consistency.

Regular Oil Testing: Establish scientific offline testing procedures (e.g., per GB/T 7595/IEC 60422), monitoring routine parameters including breakdown voltage, micro-water content, dielectric dissipation factor (tan δ), acid number, dissolved gas analysis (DGA), etc. Implement rapid response to abnormal indicators.
Online Monitoring Technology: Deploy online monitoring devices for parameters like oil moisture content, dissolved gas, and micro-particle count, enabling real-time visualization of oil condition and transitioning from time-based to condition-based maintenance.

Purification and Regeneration: Employ vacuum oil processing units (incorporating efficient dehydration, degassing, and precision filtration modules) for periodic oil filtration to remove moisture, gases, and solid contaminants. For oils with excessive acid number or tan δ but relatively mild aging, utilize adsorption regeneration (e.g., molecular sieve, silica gel treatment) or thermosiphon oil purifier technology to restore performance and extend oil change intervals.
Scientific Oil Replacement: Strictly execute oil replacement procedures according to specifications when oil degradation is severe or aging by-products cannot be effectively removed. Ensure new oil meets standards before injection, and strictly control dust and moisture during the replacement process.

Sealing Upgrade: Replace traditional materials with aging-resistant EPDM (Ethylene Propylene Diene Monomer) or fluoroelastomer seals, optimizing seal structure design for interfaces like flanges, valves, and bushings. For large transformers, equip with bellows-type conservator tanks (featuring dual-seal technology) to compensate for oil volume changes, maintain positive pressure, and completely isolate against external air and moisture intrusion.
Environmental Control: Install high-efficiency desiccant breathers (using silica gel/activated alumina) at tank vents, and regularly inspect/replace desiccant to ensure no moisture ingress during breathing. Maintain transformer rooms/oil pits dry and clean.

III. Implementation Benefits and Advantages

Direct Benefits: Significantly slow down the aging rate of the insulation system, maintaining high and stable insulation strength; drastically reduce dielectric losses and localized overheating risks caused by oil degradation; effectively suppress the development of internal latent faults (e.g., moisture ingress, impurity discharges).
Long-Term Value:

Enhanced Reliability: Substantially reduce unplanned outage rates caused by insulation or oil quality issues, ensuring continuous grid power supply capability.
Optimized Economic Efficiency: Extend major overhaul and oil change intervals, reducing maintenance resource consumption; significantly postpone the need for large-scale retrofits or replacements (enhancing lifecycle value).
Extended Lifespan: Comprehensive measures effectively delay the aging of critical components, enabling transformers to reach or exceed design life (extending lifespan by 5 to 15 years depending on operating conditions).
Safety Compliance: Meet mandatory requirements for insulation performance and oil quality management stipulated in electrical equipment preventive testing regulations and environmental laws.

IV. Quality Assurance and Implementation

Stringent Supplier Selection: Procure key materials (insulation paper, oil, seals) from top-tier brands possessing authoritative certifications (UL, VDE, CESI, etc.).
Standard Operating Procedures (SOP): Develop detailed operating specifications for insulation handling, vacuum oil filling, seal installation, and oil sampling/testing, with mandatory training enforcement.
Digital Platform Support: Utilize condition monitoring data management systems for trend analysis, enabling predictive maintenance decision support.
Expert Consultation: Provide full-cycle professional technical services, from solution customization to on-site guidance.